A barrel spring is also a type of compression spring used to produce linear force .Barrel springs are usually made of Carbon, Brass, Beryllium Copper and other alternative materials. Barrel Spring wire size varies from 0.25" to 0.250" & above, diameter varies from 0.375" to 4.00" & above. Finishing is done by plain, zinc, gold and silver, cadmium, powder coat, black oxide, and paint. These springs are mainly used in the automotive, aerospace, agriculture, turbine and marine industries.